Qt wiki will be updated on October 12th 2023 starting at 11:30 AM (EEST) and the maintenance will last around 2-3 hours. During the maintenance the site will be unavailable.

How to use FFTW: Difference between revisions

From Qt Wiki
Jump to navigation Jump to search
(Fixing incorrect chars in the instructions)
No edit summary
 
(2 intermediate revisions by one other user not shown)
Line 1: Line 1:
{{Cleanup | reason=Auto-imported from ExpressionEngine.}}
[[Category:HowTo]]
== Getting Started ==


[[Category:Learning::HowTo]]
'''Note that this is done on an Ubuntu operating system, on Windows some steps are different.'''


= How to compute FFT using FFTW in Qt =
* '''Step 1''': Download FFTW from http://www.fftw.org/download.html


== Getting Start ==
* '''Step 2''': Extract and Configure it (my path: /home/jafarabadi/Documents/fftw-3.3.4)


'''Note that I do this in Ubuntu operating system, in Windows some steps are different.'''
<pre>
cd /home/jafarabadi/Documents/fftw-3.3.4
./configure
make
make install
</pre>


* Step1: Download FFTW ([[http://www.fftw.org/download.html]])
* Alternatively install fftw through your package manager (e.g. pacman -Sy fftw)


* Step2: Extract and Configure it (my path: /home/jafarabadi/Documents/fftw-3.3.4)
* '''Step 3''': Add library to project: first open [your_project_name].pro file in Qt Creator and add this line:
<code>cd /home/jafarabadi/Documents/fftw-3.3.4
 
chmod +x configure
<pre>
./configure
LIBS += -lfftw3
make
</pre>
make install</code>


* Step 3: Add library to project: first open [your_project_name].pro file in Qt Creator and add this line:
* '''Step 4''': Example
<code>LIBS += -lfftw3</code>


* Step 4: Example
<code>
<code>#include <fftw3.h>
#include <fftw3.h>
int N;
int N;


Line 43: Line 47:
fftw_free(out);
fftw_free(out);


// A short tutorial: http://www2.math.uu.se/~figueras/fftw_tutorial/text/fftw_tutorial.pdf</code>
// A short tutorial:
// http://www2.math.uu.se/~figueras/Other/text/fftw_tutorial.pdf
</code>

Latest revision as of 07:58, 10 March 2017

Getting Started

Note that this is done on an Ubuntu operating system, on Windows some steps are different.

  • Step 2: Extract and Configure it (my path: /home/jafarabadi/Documents/fftw-3.3.4)
cd /home/jafarabadi/Documents/fftw-3.3.4
./configure
make
make install
  • Alternatively install fftw through your package manager (e.g. pacman -Sy fftw)
  • Step 3: Add library to project: first open [your_project_name].pro file in Qt Creator and add this line:
LIBS += -lfftw3
  • Step 4: Example
#include <fftw3.h>
int N;

// Set N to the number of complex elements in the input array

fftw_complex *in, *out;
in = (fftw_complex *)fftw_malloc(sizeof(fftw_complex) * N);
out = (fftw_complex *)fftw_malloc(sizeof(fftw_complex) * N);

// Initialize 'in' with N complex entries

fftw_plan my_plan;
my_plan = fftw_plan_dft_1d(N, in, out, FFTW_FORWARD, FFTW_ESTIMATE);
fftw_execute(my_plan);

// Use 'out' for something

fftw_destroy_plan(my_plan);
fftw_free(in);
fftw_free(out);

// A short tutorial:
// http://www2.math.uu.se/~figueras/Other/text/fftw_tutorial.pdf